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Lars F
 
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Default The Sample Covariance

Hi again! I want to calculate the sample covariance but the only formula I
can find is COVAR and that formula seems to calculate the population
covariance which differs slightly.

Is there a ready made formula for sample covariance?

If not, I need so summarize the products between each pair of observations
after deducting their mean respectively. I understand that for a "simple
product" you can use an array formula like {=sum(B3:B6*C3:C6)} However, I
need to subtract the mean first from each pair....I tried with
{=sum((B3-$B$10):(B6-$B$10)*(C3-$C$10):(C6-$C$10))}

Well, didn't really beleive in it...but thought it was worth trying. Any
better suggestions?

Regards,

/Lars
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Jerry W. Lewis
 
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Default The Sample Covariance

I agree, it is surprising that Excel does not have a sample covariance
funtion, but why would you want to calculate it from scratch?

Why not just calculate COVAR*n/(n-1) ?

Jerry

Lars F wrote:

Hi again! I want to calculate the sample covariance but the only formula I
can find is COVAR and that formula seems to calculate the population
covariance which differs slightly.

Is there a ready made formula for sample covariance?

If not, I need so summarize the products between each pair of observations
after deducting their mean respectively. I understand that for a "simple
product" you can use an array formula like {=sum(B3:B6*C3:C6)} However, I
need to subtract the mean first from each pair....I tried with
{=sum((B3-$B$10):(B6-$B$10)*(C3-$C$10):(C6-$C$10))}

Well, didn't really beleive in it...but thought it was worth trying. Any
better suggestions?

Regards,

/Lars


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